Temperature induced shift in the pinch-off voltage of mesoscopic devices

TL;DR

This study reveals a universal temperature-induced downward shift in the pinch-off voltage of mesoscopic GaAs devices, originating from the surrounding 2D electron gas, observed across various structures and measurement setups.

Contribution

It uncovers a previously unreported thermal effect on conductance characteristics in mesoscopic GaAs devices, emphasizing the role of the surrounding 2D electron gas.

Findings

Shift in gate voltage with temperature up to 10 K

Universal effect across different device structures

Originates from surrounding 2D electron gas

Abstract

Detailed experimental studies of the conductance of mesoscopic GaAs devices in the few-mode regime reveal a novel thermal effect: for temperatures up to at least 10 K the measured gate characteristics, i.e. conductance $G$ versus gate voltage $V_g$, exhibit a systematic downward shift in gate voltage with increasing temperature. The effect is 'universal', in the sense that it is observed in different modulation doped GaAs/GaAlAs heterostructures, in different device geometries, and using different measurement setups. Our observations indicate that the effect originates in the surrounding 2D electron gas and not in the mesoscopic devices themselves.